1. Field of the Invention
The present invention relates to a wafer dividing method of dividing a wafer into individual chips.
2. Description of the Related Art
A plurality of devices such as ICs and LSIs are formed on the front side of a wafer so as to be partitioned by a plurality of division lines. The wafer is divided into the individual devices by a cutting apparatus or a laser processing apparatus. These devices are widely used in various electrical equipment such as mobile phones and personal computers. As a method of dividing the wafer into the individual devices, there has been proposed and put into practical use a technique of applying a laser beam having a transmission wavelength to the wafer in the condition where the focal point of the laser beam is set inside the wafer at the positions corresponding to the division lines, thereby forming a plurality of modified layers inside the wafer along the division lines and next applying an external force to the wafer to thereby break the wafer along the modified layers as break start points, thus obtaining the individual devices (see Japanese Patent No. 3408805, for example).